A replicated, controlled, paired study of wheat field edges on 10 farms from 1992 to 1993 in the Netherlands (de Snoo & de Leeuw 1996) found that unsprayed field margins had greater insect diversity and abundance in the upper parts of plants than sprayed margins. The average number of insect groups was higher in the unsprayed margins (12-14) than sprayed margins (8-11). Insect density was also significantly higher in the unsprayed winter wheat margins (31-41 vs 10/100 m). Of the 18 groups found on 50% of the sites, 11 in 1992 and 9 in 1993 were significantly more abundant on unsprayed edges. The greatest effect was on flower-visiting insects and aphid predators (unsprayed: 62-73% of all insects, sprayed: 24-32%). Only three groups (long-legged flies (Dolichopodidae), crane flies (Tipulidae) and moths (Heterocera)) were less abundant in the unsprayed edges. Strips 6 m x 450 m along field edges were left unsprayed by herbicides and insecticides and were compared to sprayed edges in the same field. Insects were sampled once or twice in June. Ten sub-samples, 1.5 m from the field edge, were taken using a sweep net (total area sampled 20 m²/100 m). Aphid (Aphidoidea) abundance and dispersal was also recorded, but results are not presented here. This study was part of the same experimental set-up as (de Snoo et al. 1994, de Snoo 1996, de Snoo 1997, de Snoo et al. 1998, de Snoo 1999).